Armhole reinforcement
Stabilizing armhole curves using fusible bias tape to prevent stretching during wear.
Where it is used
1. Reinforce the pattern pieces
p. 4- Reinforce the pattern pieces: attach interfacing to the plackets and collar, and fuse the collar to the seam allowance along the entire stitching perimeter. To help prevent stretching at the shoulder seam: Attach a strip of fusible interfacing with a knit base, 0.5 cm wide and as long as the shoulder edge, to the shoulder edge of the back piece (or insert a silicone tape under the seam for reinforcement).

Securing Armhole Seam Allowance
p. 11- Sew the seam allowance at the armhole area, pressing the allowance toward the back.

Armhole Reinforcement
p. 7- On the wrong side, reinforce the armhole edges with bias fusible tape. Beforehand, make a few small snips along the tape where it curves (at the side panel area).

Related terms
requiresFusible bias tape
requiresIron and ironing board